Error #1009 after upgrading from 5.5.6 to 5.8.0

Environment:

• vCenter Server 5.1.0-1123961
• ESXi 5.1.0-1065491
• VDP 5.5.6.180

Followed the usual upgrade procedure:

1. VDP Appliance snapshotted
2. Mounted ISO containing 5.8.0 upgrade
3. Started upgrade from service web console

The problem: logging in on vSphere Webclient produces an "Error #1009" as follows...

Found this KB about "wrong URLs informed on vApp properties", but VDP is not an vApp and there is no such configuration... how can this be fixed without upgrade vCenter Server to 5.5u2?

Update #1: now even rolling back the snapshot to VDP 5.5.6, the vCenter Server still shows the Error #1009... and is also showing the wrong version information on it. Any help we'll appreciate.

Regards,

FABrizzolla